ext2fs: add read-write support for Extended Attributes.

Extended attributes and their particular implementation in linux are
different from FreeBSD so in this case we have started diverging from
the  UFS EA implementation, which would be the natural reference.

Depending on future progress implementing ACLs this approach may change
but for now bring to the tree an implementation that is consistent and
can be tested.

Submitted by:	Fedor Uporov

Differential Revision:	https://reviews.freebsd.org/D10460

1 files changed, 38 insertions, 17 deletions

diff --git a/sys/fs/ext2fs/ext2_extattr.h b/sys/fs/ext2fs/ext2_extattr.h
index 94091ed8ef40..50ab6908a0de 100644
--- a/sys/fs/ext2fs/ext2_extattr.h
+++ b/sys/fs/ext2fs/ext2_extattr.h
@@ -30,25 +30,34 @@
 #define	_FS_EXT2FS_EXT2_EXTARTTR_H_
 
 /* Linux xattr name indexes */
-#define	EXT4_XATTR_INDEX_USER				1
+#define	EXT4_XATTR_INDEX_USER			1
 #define	EXT4_XATTR_INDEX_POSIX_ACL_ACCESS	2
 #define	EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT	3
-#define	EXT4_XATTR_INDEX_TRUSTED			4
-#define	EXT4_XATTR_INDEX_LUSTRE				5
-#define	EXT4_XATTR_INDEX_SECURITY			6
-#define	EXT4_XATTR_INDEX_SYSTEM				7
-#define	EXT4_XATTR_INDEX_RICHACL			8
-#define	EXT4_XATTR_INDEX_ENCRYPTION			9
+#define	EXT4_XATTR_INDEX_TRUSTED		4
+#define	EXT4_XATTR_INDEX_LUSTRE			5
+#define	EXT4_XATTR_INDEX_SECURITY		6
+#define	EXT4_XATTR_INDEX_SYSTEM			7
+#define	EXT4_XATTR_INDEX_RICHACL		8
+#define	EXT4_XATTR_INDEX_ENCRYPTION		9
 
 /* Magic value in attribute blocks */
 #define EXTATTR_MAGIC 0xEA020000
 
+/* Max EA name length */
+#define EXT2_EXTATTR_NAMELEN_MAX		255
+
+/* EA hash constants */
+#define EXT2_EXTATTR_NAME_HASH_SHIFT		5
+#define EXT2_EXTATTR_VALUE_HASH_SHIFT		16
+#define EXT2_EXTATTR_BLOCK_HASH_SHIFT		16
+
+
 struct ext2fs_extattr_header {
 	int32_t	h_magic;	/* magic number for identification */
 	int32_t	h_refcount;	/* reference count */
 	int32_t	h_blocks;	/* number of disk blocks used */
 	int32_t	h_hash;		/* hash value of all attributes */
-	uint32_t	h_reserved[4];	/* zero right now */
+	uint32_t h_reserved[4];	/* zero right now */
 };
 
 struct ext2fs_extattr_dinode_header {
@@ -56,21 +65,15 @@ struct ext2fs_extattr_dinode_header {
 };
 
 struct ext2fs_extattr_entry {
-	uint8_t	e_name_len;			/* length of name */
+	uint8_t	e_name_len;		/* length of name */
 	uint8_t	e_name_index;		/* attribute name index */
 	uint16_t	e_value_offs;	/* offset in disk block of value */
 	uint32_t	e_value_block;	/* disk block attribute is stored on (n/i) */
 	uint32_t	e_value_size;	/* size of attribute value */
-	uint32_t	e_hash;			/* hash value of name and value */
-	char	e_name[0];			/* attribute name */
+	uint32_t	e_hash;		/* hash value of name and value */
+	char	e_name[0];		/* attribute name */
 };
 
-#define EXT2_IHDR(inode, raw_inode) \
-	((struct ext4_xattr_ibody_header *) \
-	    ((void *)raw_inode + \
-	    EXT4_GOOD_OLD_INODE_SIZE + \
-	    EXT4_I(inode)->i_extra_isize))
-
 #define EXT2_IFIRST(hdr) ((struct ext2fs_extattr_entry *)((hdr)+1))
 
 #define EXT2_HDR(bh) ((struct ext2fs_extattr_header *)((bh)->b_data))
@@ -85,10 +88,20 @@ struct ext2fs_extattr_entry {
 	(((name_len) + EXT2_EXTATTR_ROUND + \
 	    sizeof(struct ext2fs_extattr_entry)) & ~EXT2_EXTATTR_ROUND)
 
+#define EXT2_EXTATTR_SIZE(size) \
+    (((size) + EXT2_EXTATTR_ROUND) & ~EXT2_EXTATTR_ROUND)
+
 #define EXT2_EXTATTR_NEXT(entry) \
 	( (struct ext2fs_extattr_entry *)( \
 	    (char *)(entry) + EXT2_EXTATTR_LEN((entry)->e_name_len)) )
 
+int ext2_extattr_inode_delete(struct inode *ip, int attrnamespace,
+    const char *name);
+
+int ext2_extattr_block_delete(struct inode *ip, int attrnamespace,
+    const char *name);
+
+int ext2_extattr_free(struct inode *ip);
 int ext2_extattr_inode_list(struct inode *ip, int attrnamespace,
     struct uio *uio, size_t *size);
 
@@ -101,4 +114,12 @@ int ext2_extattr_inode_get(struct inode *ip, int attrnamespace,
 int ext2_extattr_block_get(struct inode *ip, int attrnamespace,
     const char *name, struct uio *uio, size_t *size);
 
+int ext2_extattr_inode_set(struct inode *ip, int attrnamespace,
+    const char *name, struct uio *uio);
+
+int ext2_extattr_block_set(struct inode *ip, int attrnamespace,
+    const char *name, struct uio *uio);
+
+int ext2_extattr_valid_attrname(int attrnamespace, const char *attrname);
+
 #endif	/* !_FS_EXT2FS_EXT2_EXTARTTR_H_ */